This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. INTRODUCTION:The usual surgical repair techniques (so-called "open technique") for anterior tracheal wall collapse are often associated with a high rate of morbidity, and prolonged stenting can aggravate the ongoing tracheal inflammation and serve as a potential source for a new stenosis. We are currently studying the laser dosimetry and the design of the surgical device for endoscopic laser cartilage reshaping minimizing the thermal damage of cartilage tissue. OBJECTIVE: In order to provide a better understanding of laser-induced tracheal cartilage reshaping, we examined the relationships between the tissue viability and the laser dosimetry as well as the change in mechanical property due to endoscopic laser exposure. In addition, we design an effective endoscopic surgical device for laser tracheal cartilage reshaping. MATERIALS AND METHODS: Tracheal cartilage extracted from New Zealand rabbits, were exposed to diode laser (wavelength =1450nm, 0.03-0.14W/mm2, Candela Corp. MA) for 3-5 seconds. The change in the mechanical property was measured using an ELF 3200 mechanical testing instrument (EnduraTEC, Minnetonka, MN) and its viability was determined using a laser scanning microscope (LSM510 Meta, Carl Zeiss Inc., Germany).